A car and a van were involved in a collision in Battle Road at the junction of Blackman Avenue, in St Leonards, at 6.38pm on Friday (January 4).
At the time of the collision, the traffic lights were not working due to a fault with an underground cable earlier in the day.
Sussex Police said the collision involved a blue Ford Transit and a white Fiat 500.
The driver of the Fiat, a 44-year-old man from Bexhill-on-Sea, was taken to the Conquest Hospital in Hastings for treatment to a fractured sternum, according to police.
A 35-year-old woman and a 13-year-old girl, who were passengers in the Fiat, were taken to hospital for a precautionary check up for minor injuries.
Crews from East Sussex Fire and Rescue Service joined Sussex Police and the South East Coast Ambulance Service (SECAmb) at the scene.
A spokesman for SECAmb said six patients were treated following the collision and ‘at least four’ were taken to Conquest Hospital for further treatment.
The spokesman said the patients were suffering from chest and shoulder pain.
A fire service spokesman said: “Two Hastings appliances were sent to a road traffic collision involving two motor vehicles on Friday at 6.38pm.
“No-one was trapped and crews made the area safe. The incident was left with the police.”
UK Power Networks said it attended the scene at 8.10am after reports of the faulty cable were made and power was returned to the properties shortly after.
Neither UK Power Networks or East Sussex Highways could confirm if power was returned to the traffic lights but witnesses said the lights were still not working at 7pm.
On Monday (January 7), a spokesman for UK Power Networks said the discovery of ‘a secondary fault’ prevented power being restored to the traffic lights and the cable was not repaired until 11pm.
Video taken at the scene on Friday showed vehicles approaching the junction with caution before travelling through the faulty lights.
East Sussex Highways said it attended the scene but, after discovering it was a power issue, ‘left it with UK Power Networks’.
Anyone who witnessed the incident is asked to report online or call 101 quoting serial 969 of 04/01.